Sift-proof bag



March 1 1927.

T. M. AVERY Y SIFTPROOF BAG Filed June 26, 1925 Patented 1, 1927. l UNITED STATES PATENT oFFlcE.

TRUE M. AVERY, HUDSON FALIS, NEW YORK, ASSIGNOR TO UNION BAG- & PAPER CORPORATION, OF HUDSON FALLS,v NEW YORK, A CORPORATION 0F NEW JERSEY.

' siFT-Pnoor BAG;

Application led .Tune 26, 19,25. Serial No. 39,824.

The present invention relates to improvements in paper bags. of the square-bottom type which have pleats or tucks in the opposite edges thereof, and the object of the invention is to provide a novel and improved bag of this type which' shall have a s1ftproof bottom.

Bags of this type have generally been'.

made `by feedinga-lat strip of aper to a former and bending or folding t e longitudinal edges of the strip over the former to produce a tube, cut-od mechanism acting to sever the tube into bag sections. of appropriate length, afterwhich an end of each bag section is pasted and folded against a side of the bag to form the closure for the bottom thereof. Heretofore, it has been customary, in manufacturing bags of this type, to make the side of the bag on which the longitudinal seam is formed and against which the bottom fold is pasted, somewhat narrower than the opposite or face side, but it has been found that in so doing, the corners of the bottom -fold which were wider f than the seam side of the bag projected laterally-beyond the longitudinal edges thereof, so that while the remainder of the bottom fold was pasted to the seam side of the bag there was no backing `or support against which the corners of the fold could be pasted, in consequence of which said corners of the bottom foldremained unpasted and unsecured, and left crevices through which powdery or granularmaterial placed in the bag would sift out, thus causing a'loss in the contents of the bag and being otherwise objectionable.

I The present invention produces a siftproof bag thus overcoming theobjections found to exist respectingbags of this ytypeas heretofore manufactured. According to the present invention, the seam side of the bag,` against which the bottom fold is pasted,

. is made Wider thanthe opposite side or face thereof, thus providing a backing or support of av width at least equal to the full. width of the bottom fold, andthe .corners of the bottom fold, as well as the remainder thereof, are pasted against the marginal portions of the backing or support thus provided, thereby producing a closure of the bottom fold throughout its width, including its corners, which renders the bag sift-proof.

In the accompanying drawing Figure 1 is a view of the rear of a squarebottom bag made -in accordance with the present invention, one corner on the bottom fold being shown by the full 'lines as-turned back and by the dotted. lines in pasted position.

Figure 2 represents a longitudinal section through the bagtaken on the line 2-2 of Figure 1. i Y

Figure 3 is a. detail perspective View of one of the lower corners of the bag made as shown in Figures 1 and'2, this figure illustrating the manner in which one of the corners of the bottom fold is pasted to the seamedvside or rear face of the bag.

Figure 4 is a View of one end of a bag One embodiment of the invention Vis shown Y in ,the accompanying drawing and willvbe hereinafter described in detail, but it is to be understood that equivalent bag structures are contemplated and such will be in cluded Within the scope Aof the claims.

In the present instance, l designates the face side and 2 designates the seam side of a'square-bottom bag, 3 designating the seam, and 4 designates the pleatsor tucks which are formed in the longitudinal 'edges of the bag, the bag being` of a well-known'type which is usually manufactured by feeding aY strip of paper to a former and foldinv the longitudinal edges of the striparound the former to produce a paper'tube from which the bag sections may be cut. The pleats or tucks 4 are formed in .the longitudinal edges of the paper tube as the same is made on the loo former. A cut-off device, the construction" I and operation of which are well-known in the art, serves to sever the paper tube into appropriate lengths to serve as bag sections,

the bag, which Iforms a bottom lia 8, against a side of the bag. Heretofore, tie back or seam side 2 of the bag has been made somewhat narrower than the opposite side or face 1. But in folding the bottom Hap of such a bag against the back or seam side thereof, the corners cf the bottom flap projected beyond the longitudinal edges of the back or seam side of the bag, and, in consequence, these corners of the bottom iap were left unpasted with respect to the body of the bag as there was no part of the back or seam side of the bag to receive these corners of the flap. As a result, bags made in that manner were not leak-proof as powdery or granular material placed in such bags could escape hrough the unpasted corners of the bottom ap. c

According to the present invention',Y the back or scam side 2 of the bag, as will be seen from Figures 1 and 2` is wider than the opposite side or face 1. The bottom liap` or fold 8, which is turned upwardly against and pasted to the back or seam side 2 of the bag is narrower across its corners 8a than the width of the baekor seam side 2, and, hence, these corners'of the bottom liap or fold` when folded against the back of the bag will be removed inwardly from the longitudinal edges of the back of the bag and the latter will provide supports' of ample area against which. these corners of the bottom fiap or fold may be pasted. Bv thus providing a support or backing of suliicient width at the -baek of the bag to receive the corners of the bottom flap or fold, eective sealing and securing of these corners of the flap or fold are insured. The edges 6 of the pleats or tucks will lie beneath the bottom fold 8 and will be pasted also to the back or rear face of the bag. As the corners 2 of the tucks are produced by continiations of the longitudinal edges of the back or seamside 2 of the bag, these corners. when folded and pasted against the back of the bag will be received within the width thereof, thus insuring ample backing or support against which these corners of the tucks will be pastedand thus sealed and secured. Moreover, the ends of the tucks are overf lapped by the outer portion of the bottom ceived within the width of the back or seam side 2 of the bag and pasted thereto. These ligures also show the corners 2 received within the width of the back or rear side 2 and pasted thereto.

The paste to secure the bottom fold or 'lap may be applied either to the iiap, to substantially cover it from the fold line A--B to its edge 5, or it may be applied to the back 2 of the bag above the fold line A-B toI cover a suiiieient area to insure pasting of all the edges of the ap and the tucks or pleats.

The present invention enables square-bottom bags of the type having pleats or tucks in their edges to be produced which will be sift-proof, thus overcoming the objection previously existing in bags of this type, although the bags may be manufactured as expeditiously and inexpensively as heretofore.

I claim as-my invention l. A square-hottoin paper bag comprising a tube-like body having a pleat or tuck at each edge, and a bottom flap folded and pasted against a side of the body of the bag, the side of the bag against which the bottom iiap is pasted being wider than the opposite side ot the bag and providing supports against which the corners of the bottom flap are pasted.

2. A square-bottom paper bag comprising a body having a longitudinal seam at one side and a pleat or tuck in each longitudinal edgethereof, and a bottom Hap folded and pasted against the seam side of the bag, the seam side of the bag being wider than the opposite side thereof and providing portions within its width to which the corners of the bottom Hap are pasted.

In testimony whereof I have hereunto set my hand' TRUE M" AVERY 

